Nitrogen Excretion and Ammonia Emissions from Pigs Fed Reduced Crude Protein Diets or Yucca Extract

Iowa State University Animal Industry Report 2005. Dietary strategies are an important part of management systems designed to reduce ammonia emitted from animal feeding operations. Two potential strategies (reducing dietary crude protein content and adding yucca extract to the diet) were evaluated in two swine feeding trials. Three groups of pigs were housed in environmental chambers in order to allow for direct measurement of ammonia emissions. Emission rates and excreta nitrogen and ammonium concentrations were analyzed. Feeding a diet with four amino acids resulted in large though nonsignificant reductions in ammonia emissions, and affected excreta nitrogen concentrations; increasing urinary ammonium-N while decreasing urinary and fecal total nitrogen and fecal ammonium-N. The only significant effect of dietary yucca was a decrease in urinary ammonium-N concentration. In both studies, ammonia emission rates increased over time as manure accumulated in the chamber pits.